Test setups running protocol compliance toolsets may be used to examine the performance of user equipment operating according to one or more predefined standards, for example to test and certify that user equipment conforms to the relevant standard(s). The toolsets may be used to define scripts representing configuration scenarios and to run interoperability tests and development tests to examine conformance. For example, a system for emulating LTE-Advanced Carrier Aggregation can be provided, in which the Component Carriers (base stations or cells) being aggregated reside on multiple hardware units or transceivers.
LTE-Advanced Carrier Aggregation is a 3GPP Release 10 feature introduced to increase the data rates which can be achieved by a connected device such as an LTE-Advanced capable mobile (UE). With Carrier Aggregation, UE is simultaneously connected to multiple cells (referred as Component Carriers in 3GPP terminology). A maximum of 5 such Component Carriers can be aggregated. Both intra- and inter-band Carrier Aggregation is envisaged i.e. the cells being aggregated can be on different RF frequencies. Some emulation scenarios for Carrier Aggregation are implemented by interconnecting multiple transceiver units implementing the physical layer of the aggregated Component Carriers. These multiple transceiver units are controlled by a common MAC scheduler via an interconnect mechanism such as an Ethernet switch.
When in a connected state with the network, UE can be configured to periodically send channel status information about the quality of the channel as affected by propagation conditions and interfering sources. Such channel status information is of different types:
a) Rank Indicator/Precoding Type Indicator (RI/PTI) bits, which indicate the optimum number of independent downlink data streams which can be received at the UE;
b) Channel Quality Indicator/Precoding Matrix Indicator (CQI/PMI) bits, which provide a measure of the interference conditions and preferred ratios of information bits versus channel capacity (channel coding rate).
Some emulation scenarios require implementation of configurations where values of periodic CQI/PMI are conditioned by the last reported values of RI/PTI. Hence, the most recently reported value of RI/PTI is necessary to ensure successful decoding of subsequent subframes with CQI/PMI transmissions.